Solar flares are the most powerful events occurring in our Solar System, capable of pushing the charged particles to almost light speeds. They are produced by a sudden energy release from magnetic fields in the Sun's atmosphere. When they explode, massive energy amounts get released and magnetic fields reconfigure themselves again in the ‘magnetic re-connection’ process. The mechanism of how this energy release induces such high speed particle flows has puzzled Earthly astronomers. According to newest observations, the acceleration of charged particles happens in a region of the flare where rapidly flowing solar gases impinge on dense magnetic field loops. During this process, a strong shock, the so-called ‘termination shock’ is generated. It pushes the particles into super high speeds.
The VLA telescope is capable of observing the Sun in a broad range of radio frequencies within time intervals of 50 milliseconds and producing over 40,000 individual radio images during one second of observation. It has revealed that short-lived radio waves outbursts are generated by energetic electrons. "These new insights are a significant step forward in our understanding of particle acceleration, which is not only an important aspect of solar flares, but also a fundamental physical process occurring throughout the Universe," Chengcai Shen, a researcher at the CfA said.
Reference: "Particle acceleration by a solar flare termination shock" - Bin Chen1, Timothy S. Bastian, Chengcai Shen, Dale E. Gary, Säm Krucker, Lindsay Glesener - Science (2015) - DOI: 10.1126/science.aac8467
IMAGE (R) This image shows the speed of fast plasma outflows produced by the flare. The termination shock is shown as a transition layer where the colors change abruptly from red/yellow to blue/green. At bottom is the Karl G. Jansky Very Large Array, which captured the termination shock in action using radio observations. Image credit: SDO/AIA data is from NASA. VLA image courtesy of NRAO/AUI. Image prepared by Chen, Jibben, and Samra.